1st and Ten Line – How it Works

The simplicity of the line pales in comparison to the technology that makes it work.

The 1st and Ten Line, the Famous Yellow Line that shows television viewers how far the team with the ball must go to make a first down, has become part of the culture of watching professional or college football on TV. With a 98% fan approval rating, the Yellow Line has become a broadcast enhancement that fans simply can’t live without. But, how do they do that?

The simplicity of the line pales in comparison to the technology that makes it work. The trick is to make the line seem painted on the field and to have the players appear to run over it. What looks like on screen magic is actually a complex technology that requires a lot of human and computer horsepower from Sportvision, Inc., creator of the Yellow Line. Here’s how it works … in layman’s terms.

A laser placed in the center of the field is used to collect data on elevation points. That information is used to draw a computer map of the contours of the field, and the map is adjusted and overlaid onto the camera’s view of the actual field. Anywhere from three to five separate broadcast cameras are outfitted with custom Sportvision sensors and encoders to capture camera data so that the 1st and Ten Computers can enhance one camera “live” with the yellow line, and any of the others for use in replay. As cameras pan, tilt and zoom, this data enables the virtual line to follow suit, staying in perspective and getting larger and smaller, as needed.

Drawing the yellow line so that it appears to be painted on field underneath the players is accomplished through a sophisticated process of color keying that allows the operators to tell the computers what colors to draw on (grass, dirt) and what not to draw on (skin, uniforms). And finally, after adding the precise location of the first down marker to the system and... voila … The Yellow Line appears like magic on your TV screen.